Kinetics of isomerization

The three cycles have to turn over in the same range of temperature. This catalytic approach of the DeNOx reaction is not new. There is the same process for isomerization of alkanes, where there are also 3 catalytic cycles which have to turn over simultaneously (bifunctional catalysis). The kinetics of isomerization is given by only one cycle, the other two turning over very rapidly and are near equilibrium [13]. 

Ray, J. D. (1962). Heat of isomerization of peroxynitrite to nitrate and kinetics of isomerization of peroxynitrous acid to nitric acid. J. Inorg. Nttcleotide Chem. 24, 1159-1162. 

A study of the kinetics of isomerization of n-pentane at 372°C. over a platinum on alumina catalyst (0.3% platinum) has been reported by Sinfelt et al. (S4). The rate measurements were made in a flow system at low conversion levels (4-18%). The n-pentane was passed over the catalyst in the presence of hydrogen at total pressures ranging from 7.7 to 27.7 atm. and at hydrogen to n-pentane ratios varying from 1.4 to 18. Over this range of conditions the rate was found to be independent of total pressure and to increase with increasing n-pentane to hydrogen ratio (Fig. 4). The rate data were correlated by an expression of the form... 

It is of interest to consider the kinetics of isomerization at low hydrogen pressures in more detail. In the case of isomerization-dehydroisomerization of methylcyclopentane at low hydrogen pressures, it has been proposed (SI) that the rate-limiting step is the formation of intermediate methyl-cyclopentenes via the reaction scheme ... 

Kinetics of isomerization of glyceraldehyde to dihydroxyacetone—and the formation of pyruvaldehyde from both—have been studied in sub- and super-critical water.191... 

M—ONO) and nitro (M—N02) isomers of some acidoammine-cobalt(III) complexes. Many years later Adell2 made extensive studies of the kinetics of isomerization in these systems. However, it was not until 1962 that linkage isomers of other metal complexes of this type were reported. ... 

A study of the kinetics of isomerization of nitroaminothiazoles [227-229] showed that both intramolecular and intermolecular migration of the nitro group occur [228], The following reaction mechanism was proposed (Scheme 22). 

Thiopyrylium ions can function as catalyst in the equilibrium isomerization between the corresponding IH- and 4//-thiopyrans, by abstracting a hydride ion as shown in Eq. (10) [77ACS(B)496 91JOC1674]. Such isomerization equilibria have also been studied theoretically by MNDO and AMI methods (91JOC4431). The kinetics of isomerization of 2,4,6-triphenyI-4//-thiopyran in the presence of 2,4,6-triphenylthiopyrylium ion has been investigated in DMF at various temperatures (81JHC1517). 

Kinetics of isomerization of glyceraldehyde to dihydroxyacetone—and the formation of pyruvaldehyde from both— have been studied in sub- and super-critical water. Formaldehyde reacts with isoeugenol [l-(3-methoxy-4-hydroxyphenyl)propene] in alkaline medium to give a 1,3-dioxane derivative via an unusual Prins-type reaction. The potential-energy surface for the equihbriimi, HCO - - HCN H2CO - - CN, has been calculated by ab initio methods. 

The kinetics of decomposition of 33 have been followed by monitoring the height of the v(C=0) vibration while the kinetics of isomerization of cis-[RuX(CO)(dppe)2] [SbFg]... 

Since the kinetics of isomerization of 195 and 196 are different, severalmech-anisms can be operating. Study of compound 196 when compared with 195 does not adduce any supplementary evidence for a pseudorotation mechanism. However, it confirms the multiplicity of exchange processes possible at silicon. 

It has been deduced that the dimensionality of stilbene isomerization may not be one-dimensional, as commonly assumed, from an examination of the kinetics of isomerization of the meta-methyl substituted derivative of stilbene in decane as a function of... 

The mechanism given above is merely a suggestion, based on presently available data, as to the function of the decomposition inhibitors in the isomerization of n-pentane. It is hoped that a systematic study of the kinetics of isomerization of saturated liquid hydrocarbons in the presence and absence of cracking suppressors, may furnish additional information about the mechanism of isomerization. 

Braude " later pointed out that mechanistic conclusions based on these early studies of allylic ester isomerization are of doubtful validity, since they do not account for the sensitivity of these reactions to adventitious acidic impurities. Braude et ti/, and Pocker " " " studied the kinetics of isomerization of a-phenylallyl esters [(3), R = = YCgH, R == H] in the weakly... 

Allylic chlorides isomerize considerably less readily than the corresponding bromides and iodides, and monosubstituted allylic chlorides such as a- and y-methyl-allyl chloride are reasonably stable. An a-aryl substituent or two alkyl substituents increases the lability of allylic chlorides considerably, and the kinetics of isomerization of a limited number of reactive allylic chlorides have been studied. 

The kinetics of isomerizations of vinyl allyl ethers have been studied in the gas phase, in solution, and in the neat liquid ether. In the gas phase, isomerization rate is independent of pressure down to about 1 torr, below which the rate diminishes with decreasing pressure in the manner characteristic of uni-molecular reactions . The rate of isomerization is not influenced significantly by glass surfaces, but is faster in solution in either non-polar or moderately polar solvents than in the gas phase. Reactivity is increased by methyl substitution of either the vinyl or the allyl group of the ether. All of the isomerizations thus far studied have negative entropies of activation, with values ranging from —8 to —13eu, Isomerization of vinyl allyl ether (neat liquid) at 130°C exhibits a volume of activation of — 18 cm. mole". Published kinetic data are summarized in Table 3. 

Reactivities of Side-chains of Monocyclic Thiophens.—The protonation of various furan- and thiophen-carboxamides in aqueous sulphur acid solution has been investigated by u.v. spectroscopy. The values of pKbh that were calculated using the acidity function and the Bunnett-Olsen linear free-energy relationship indicate the lower basicity of furan- and thiophen-2-carboxamides with respect to that of benzamides and of the 3-derivatives. The kinetics of isomerization of cw-l-(2-thienyl)-2-phenylacrylonitrile, as well as of its 2-furyl and 2-selenienyl analogues, have been studied in a solution of decahydronaph-thalene, with methanesulphonic acid and potassium t-butoxide as catalysts, and the mechanism has been discussed. ... 

The kinetics of isomerization have been described by eq 2, where and are the rate and constant of insertion of a primary unit onto an active site with a secondary chain end, and are the rate and constant of secondary chain end isomerization, and Cand are the active centers having a secondary chain end and none or one coordinated monomer... 

D. Brown and J. H. R. Clarke, /. Chem. Phys., 92, 3062 (1990). A Direct Method of Studying Reaction Rates by Equilibrium Molecular Dynamics Application to the Kinetics of Isomerization in Liquid -Butane. 

Cyclobutene has long been known to isomerize to 1,3-butadiene. The kinetics of isomerization of the parent cyclobutene were determined to be log k = 13.4 — 32900/2.3/ r (Scheme 5.8). The activation energy is more than 30 kcal/ mol lower than that for cleavage of cyclobutane (see Section 3). 

The kinetics of isomerization of complexes of type [Al(/ -diketonato)a] were studied earlier and now isomerization involving the cis- and trans-lsomevs of a related complex (15) has been studied. The trans (Ci) isomer on dissolving in CCI4 is converted into an equilibrium mixture with the cis (C3) isomer the rates of isomerization and the equilibrium positions have been determined. The intramolecular process relates kinetically to similar processes involving classical / -diketonato-ligands. 

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